A single Iranian hacker has taken credit for the operation in which fraudulent digital certificates were obtained from Comodo, saying that he hacked into the Web site via affiliates based in Italy.

"I hacked Comodo from InstantSSL.it," said the attacker in a post to text-sharing Web site Pastebin. He said the key was finding a DLL file that included a username and password for that organization's GeoTrust and Comodo account, which ultimately enabled him to submit Certificate Signing Requests (CSRs) and have them be immediately signed by Comodo.

Over the course of several rambling missives -- the latest was posted on Monday -- the attacker also identified himself as an Iranian, and said that his hack was in retaliation for Stuxnet, which he blamed on Israel and the United States. He also claimed to have securely deleted Comodo's Microsoft IIS server and multiple backups, and disavowed having any relationship to the Iranian Cyber Army.

Security experts, however, aren't convinced that he was alone. "The one remaining mystery is this: If it was a lone hacker making a point, why issue certificates for these specific Web sites, all related to secure communication methods often used by dissidents to organize protests and share news with the world?" said Chester Wisniewski, a senior security advisor at Sophos Canada, in a blog post.

Comodo has since revoked the certificates, which affected domains owned by Mozilla, Google, Skype, Microsoft, and Yahoo. But the company's business practices have drawn criticism, given how the security of its digital certificates was apparently compromised with one username and password.

Thankfully, the only activity that was seen relating to the fraudulently obtained certificates were two Online Certificate Status Protocol (OCSP) hits.
According to a blog post from Mozilla, "this suggests that the certificates have not been deployed in an attack, though it is possible that the attackers would block OCSP requests as well."

Mozilla, meanwhile, has also been criticized because it learned of the vulnerabilities on March 16, but chose to delay publicizing them until March 22, when a new version of Firefox was available that had the serial numbers of the fraudulent certificates hardcoded into a blacklist.

On Friday, Mozilla apologized for that decision. "In hindsight, while it was made in good faith, this was the wrong decision. We should have informed Web users more quickly about the threat and the potential mitigations as well as their side-effects."

But it also criticized Comodo for issuing certifications "directly from the root," and questioned the security of its Registration Authorities (RAs). "We are concerned about the amount of trust Comodo seems to have placed in RAs whose network security they did not oversee."